1. Field
The invention is in the field of apparatus and methods for applying rotational pressure to various parts of the body and particularly for use in correcting transverse plane deformaties in the hip joints and legs of the human body. Such transverse plane deformaties cause, for example, in-toedness, i.e., pigeon-toedness, or out-toedness.
2. State of the Art
It is currently known that many transverse plane deformaties of the lower limbs are caused by deformaties in the hip joints or deformaties in the tibia, i.e. the lower leg bone. Thus, in-toedness or pigeon-toedness, and out-toedness may be caused by deformaties of the hip joints, deformaties of the tibia, or deformaties in both the hip joints and tibia. It is also generally recognized that these deformaties, at least as caused by the hip joints, may be corrected, or at least partially corrected, by applying corrective pressure to the deformed hip joint while a person is young and the bones are still relatively pliable, usually prior to reaching the age of two years.
The most common apparatus in use today for applying pressure to the hip joints are the Denis Browne Bar and twister cables.
The Denis Browne Bar is a bar with two spaced apart shoes secured thereto. The shoes are rotated for the correction of in-toedness to point the toes outwardly. Thus, a child puts on the shoes on the bar and his feet, legs, and hips are rotated outwardly to put the corrective outward rotational pressure on the hip joints. The Denis Browne Bar is worn by a child while he sleeps.
Twister cables are bars that extend from a belt apparatus worn by a patient down to his shoes and again hold the shoes in a twisted position to twist the feet and legs to apply corrective pressure to the hips.
The problem with the Denis Browne Bar, twister cables, or any similar apparatus and method where rotational force is applied to the foot is that extreme rotational forces must be applied to the foot in order for any rotational force to be applied to the hip joint. This is because when the foot is rotated, rotation is taken up in the midtarsal and subtalar joints of the foot, the ankle, and then the knee, before any rotational pressure is put on the hip joint. Somewhere between twenty and thirty degrees of rotation can be absorbed in the foot before the rotational force extends beyond the foot. These abnormal rotational forces applied to the normal foot, ankle, and knee joints cause problems which may be as bad as the hip joint problems which are being corrected. For example, the rotation outwardly of the feet can cause flat feet, external tibial torsion, and knock knees.
Further, it has been found that where minor cases of in-toedness exist and it appears that the child grows out of the problem, in many cases the child has not really grown out of the problem at all, but merely corrected it by rotating other joints, such as the foot. Thus, in many instances where apparent correction of the problem has taken place, it has been found that the child has compensated by turning the foot, resulting in flat feet.
Attempts have been made to apply rotational pressure directly to the hip joints by means of devices which hold an infants legs so as to apply 90 degree or more flexion and 90 degree abduction to the hip joints (see U.S. Pat. Nos. 2,955,594, 3,114,368, 3,730,177 and 4,108,168). However, such devices are not adjustable over a wide range of hip abduction or flexion and generally are cumbersome with one device requiring the strapping of the child's chest and arms to the device as well as his legs. Further, such devices do not provide for putting rotational pressure on the tibia when the deformity is in the tibia either in addition to a deformity of the hip joint, or apart from the hip joint.
In some cases, the deformities will be in the hip joint, in other cases the deformities will be in the tibia, or in both the hip joint and the tibia. Where deformities are in both, the deformities may not be in the same direction so that it is desirable to put different rotation pressure on the hip and the tibia.
There remains a real need for an apparatus and method to put rotational pressure directly on the hip joints or directly on the tibia, without putting abnormal rotational pressures on other joints. Further, there is a need for such a device that is easy to use and may be used over a wide range of applied rotational pressures.